1. Field of the Invention
The present invention refers to a method for milking an animal by means of at least one milking machine comprising at least one teatcup having a teatcup liner forming a space defined by a wall surface, the method comprising the step of applying said teatcup to a teat in such a manner that the wall surface extends around and abuts the teat. Moreover, the invention refers to a device for milking an animal by means of at least one milking machine comprising at least one teatcup having a teatcup liner forming a space defined by a wall surface, said teatcup being arranged to be applied to a teat in such a manner that the wall surface extends around and abuts the teat.
2. Description of the Prior Art
The teatcup liners which are provided in teatcups of such milking machines defined above are subjected to a pulsating movement due to the cyclically alternating pressure level prevailing in the pulsating chamber formed in the teatcup between the outer surface of the teatcup liner and the inner surface of a teatcup shell in relation to the relatively low pressure level prevailing in the inner space defined by the teatcup liner. One says that the teatcup liner collapses cyclically. At each collapse the teatcup liner is compressed in such a manner that the milk flow through the teat is hindered.
When a teatcup liner collapses the wall of the teatcup liner is folded along two diametrically opposed, essentially vertical folding lines (flexing folds), which are relatively well defined. It is to be noted that there are also teatcup liners which are manufactured in such a manner that flexing folds are obtained at for instance three predetermined locations. In most cases, it has appeared that teatcup liners collapse at the same location at each collapse occasion, i.e. the wall of the teatcup liner is folded along the same folding lines each time. One reason for this phenomenon may be small differences in the thickness of material of the wall of the teatcup liner. In practice, such differences are not possible to avoid in teatcup liners available today by the manufacturing methods which are offered, i.e. any usual moulding method. However, even if it is possible to manufacture a teatcup liner with an absolutely uniform wall thickness a weakening arises at each collapse occasion and because thereof such predetermined positions for the flexing folds will develop.
Today, the equipment and methods are developed for automatic and voluntary milking of cows, i.e. systems where the cows are permitted to walk about freely and at need visit a milking stall having a milking robot for automatic application of the teatcups to the teats of the cow. The application may, for instance, be performed by means of a robot arm engaging and applying the teatcups successively in a determined order by means of a support frame which may be positioned by a robot arm and which comprises the four teatcups suspended by a respective small arm which is arranged to project the teatcup vertically, by means of a support frame which may be positioned by a robot arm and which comprises four teatcups which are applied successively by moving the support frame upwardly against the teats, or by means of a fixed set of teatcups which by means of a robot arm are applied simultaneously to the teats of the cow. In these cases, each teatcup will be applied to the same teat at each milking occasion with respect to one cow. In addition, the teatcup will have the same orientation with respect to xe2x80x9citsxe2x80x9d teat. This means that the folding lines mentioned above will be located at essentially the same location at each milking occasion with respect to each individual teat. Due to the fact that the teatcup liner always collapses at the same location on the teat, there is a risk of injuries on the teat, in particular with regard to the fact that the cows will be milked more frequently by the automatic milking system described above then by the previously used conventional milking methods with manual application of the teatcups.
Also in cases of, for instance, a milking parlour with several milking stalls, there is a risk that the teatcup liner will collapse at the same location on the teat at successive milking occasions, in particular in connection with a higher degree of automatization with respect to the application of the teatcups.
The object of the present invention is to provide a method and a device by which this risk of injuries may be reduced or remedied.
This object is obtained by the method initially defined and characterized in that the application of said teatcup is controlled in such a manner that an arbitrary portion of the wall surface with a significant frequency abuts different teat portions during a first milking occasion with respect to an animal and during a later milking occasion with respect to this animal, respectively. By such a method, one may avoid the collapse of the teatcup liner at the same location with respect to the teat, at least not at each milking occasion. The risk of injuries on the teat ought to be reduced even if the collapse location of the teatcup liner is not displaced at each milking occasion.
According to an embodiment of the invention, said first and second milking occasions form two successive milking occasions. According to this embodiment, the risk of the injuries mentioned above should be completely eliminated.
According to a further embodiment of the invention, the control is obtained by rotating said teatcup between the first milking occasion and the second milking occasion. Thereby, said teatcup may be rotated about a longitudinal centre axis extending through the teatcup. By rotating the teatcup in such a manner about its own axis, it may be ensured that it collapses at different locations with respect to the teat at each milking occasion.
According to a further embodiment of the invention, the control is obtained by applying said teatcup to a teat at the first milking occasion and to another teat at the second milking occasion. Since different teatcup liners collapse at different locations it is also possible to ensure with a great probability by such a measure that a teat will be subjected to a teatcup liner which collapses at different locations with respect to the teat at different milking occasions. This measure may, for instance, be realised by rotating said teatcup about an axis of rotation, which extends outside the teatcup and in parallel to a longitudinal centre axis through the teatcup.
According to a further embodiment of the invention, the method involves milking of said animal by a first milking machine at the first milking occasion and by a second milking machine at the second milking occasion.
According to a further embodiment of the invention, the application of said teatcup is performed by means of a gripping member of a device for automatic application of a teatcup to a teat of an animal. Thereby, the milking machine may comprise a set of teatcups and the control may be obtained by applying the teatcups of this set to the teats of an animal in a first order at the first milking occasion and in a second order at the second milking occasion. Said first and second order may refer to the succession by which the teatcups are engaged by means of said gripping member from a teatcup magazine which is arranged to enable storing of the teatcups between said milking occasions.
According to a further embodiment of the invention, the control is obtained by means of an identification of the animal in question at each milking occasion and by a registration of the teat portion which said portion of the wall surface of the teatcup liner abuts at said first milking occasion for determining the teat portion which said portion of the wall surface of the teatcup liner is to abut at said second milking occasion. Moreover, it is possible to obtain the control by means of a random number generator for determining the teat portion which the portion of the wall surface of the teatcup liner is to abut at the respective milking occasion.
The object is also obtained by the device initially defined and characterized by means arranged to control the application of said teatcup in such a manner that an arbitrary portion of the wall surface with a significant frequency abuts different teat portions during a first milking occasion with respect to an animal and during a later milking occasion with respect to this animal, respectively.
Advantageous embodiments of the device are set forth in the description and claims presented below.